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O2 AMP + ODAC - Page 97

post #1441 of 3247
Quote:
Originally Posted by mikeaj View Post

A lot of times, double amping is really no big deal.  I mean, it's a lot easier for an amp to drive a line input (thousands of ohms impedance, thus low current and so on) than it is for that amp to drive some actual headphones.

 

And DX I think is like D1, which has ~100 ohms output impedance.  It's supposed to be a normal line output that's driven by some high-quality audio op amp that's not particularly some high-current output part.  It's not really much of an amp in the sense that most people are talking about.


i did state that i didnt know anything about pc soundcards, and i also said that noise may be added, not that it definitely would. its just the my laptops headphone jack is really really hissy, which was one of the reasons i got an external dac/amp in the first place. so if i were to send a signal through it and into my O2 id get sound thats just as bad. this is what i was talking about.

 

entirely unrelated edit: my mouses scroll wheel stopped working about a week ago and i was all upset about getting a new one because i really like my mouse... then my roomate walked in and asked to use my printer. i obliged and when getting up to fetch a glass of water i accidentally dropped the mouse on the floor. now its working fine again! im so pleased! beyersmile.png


Edited by adamlr - 5/12/13 at 8:52am
post #1442 of 3247

When you write it disconnects ODAC, this meanst the O2 Amp is still active?

So basicaly Xonar DX is DAC and O2 is only AMP?  (sorry still audio beginner)

 

Quote:

Nah, actually the O2's input jack itself is the switch.  If you plug something in, it disconnects from the ODAC.

 

Or at least, that's how it's supposed to be.  I didn't verify myself.

 

Unless you're using CMSS-3D or whatever processing Creative offers these days, or especially EAX (rare for current titles, if I'm hearing things correctly), I wouldn't think there's much substance to claims about gaming audio.  The way you get significant changes is to change the bits that get sent to the DACs.  If you're not doing software processing that changes those bits, it's just about DAC performance, and that's a small blip in the grand scheme of things.

 

Well I might buy Creative soundcard, so I guess I would be using CMSS-3D then.

 

I play alot Counter Strike: GO, so I guess IF there is a difference between ODAC and CMSS-3D it definitively will be picked up by a competitive fps game like Counter Strike: GO

 

Maybe I'll just get the O2 ODAC and see how the position is compared to the Xonar DX, if no difference gaming then sell DX.

Maybe I also try out the Creative Titanium HD and if there is no difference with the ODAC I sell the Titaniu HD aswell

post #1443 of 3247
Quote:
Originally Posted by HiFiRobot View Post

 

Your motherboard seems to have two USB-buses. Try to move around your USB devices between ports and separate the DAC like in the picture below.

Which motherboard is it?

 


The motherboard is an AsRock Z68 Extreme 4 Gen 3, I got 2 USB 3.0 ports but they never worked (maybe because I have a Sandy Bridge processor? I don't know). Anyway I did as you said (I connected everything but the O2/ODAC on the rear of the motherboard, and the amp/dac on the front USB 2.0 port), now the O2/ODAC has his own bus. smily_headphones1.gif

 

One more question: I'm using the USB input with the PC (for music listening) and the 3.5 input with the monitor (for gaming, because my PS3 is connected to the monitor by HDMI cable). Can this configuration ruin the output sound quality? (I obviously use only a source at once, but each of them is connected 24/7).

post #1444 of 3247
Quote:
Originally Posted by adamlr View Post

i did state that i didnt know anything about pc soundcards, and i also said that noise may be added, not that it definitely would. its just the my laptops headphone jack is really really hissy, which was one of the reasons i got an external dac/amp in the first place. so if i were to send a signal through it and into my O2 id get sound thats just as bad. this is what i was talking about.

 

I don't mean to hound any point, but that's more of the source being noisy than anything to do with double amping.  (and depending on what you call an amp, there is way more than double amping going on for music production as well as playback)

 

One point to make is that some mid-high level discrete sound card like a DX is in a totally different league than some laptops' hissy onboard sound.  It gets better performance than a lot of megabucks audiophile gear.

 

Also, did you ever try the laptop with the O2?  A lot of times, the noise doesn't scale up as you turn the volume up, so if you send max volume to an external amp and turn the volume down on the amp, you can effectively turn down the noise (as compared to the source by itself)... assuming you weren't already maxing out the volume.  You can think of it as increasing the signal level more so than the noise level, so the resulting SNR is higher.

 

 

Quote:
Originally Posted by grandpatzer View Post

 

When you write it disconnects ODAC, this meanst the O2 Amp is still active?

So basicaly Xonar DX is DAC and O2 is only AMP?  (sorry still audio beginner)

 

Right, I mean that if you plug in X to the O2's input, the O2 will switch to using X.  It disconnects itself from the ODAC, so it no longer gets a signal from there.  Yes, this means Xonar DX would be DAC and O2 would be the amp.  No ODAC involved.

 

 

Quote:
Originally Posted by autior View Post

 

One more question: I'm using the USB input with the PC (for music listening) and the 3.5 input with the monitor (for gaming, because my PS3 is connected to the monitor by HDMI cable). Can this configuration ruin the output sound quality? (I obviously use only a source at once, but each of them is connected 24/7).

 

If I understand you correctly, you have PS3 ---HDMI--->  monitor ---stereo 3.5mm---> O2/ODAC combo to headphones?

 

In general, look for which connections are digital and which are analog.  This means the monitor is responsible for taking the digital audio info and doing the digital-to-analog conversion for sounds coming from the PS3.  It probably has some cheap hardware in there to do that, probably doing a worse job than the PS3 itself would, and worse than the ODAC.  This means you're relying on the monitor for D/A but using the O2 as an amp.  ODAC is bypassed.

 

But I don't think that's likely to "ruin" the sound quality.

post #1445 of 3247
Quote:
Originally Posted by mikeaj View Post

 

I don't mean to hound any point, but that's more of the source being noisy than anything to do with double amping.  (and depending on what you call an amp, there is way more than double amping going on for music production as well as playback)

 

One point to make is that some mid-high level discrete sound card like a DX is in a totally different league than some laptops' hissy onboard sound.  It gets better performance than a lot of megabucks audiophile gear.

 

Also, did you ever try the laptop with the O2?  A lot of times, the noise doesn't scale up as you turn the volume up, so if you send max volume to an external amp and turn the volume down on the amp, you can effectively turn down the noise (as compared to the source by itself)... assuming you weren't already maxing out the volume.  You can think of it as increasing the signal level more so than the noise level, so the resulting SNR is higher.

 


perhaps it is the source and not the amp, tbh i dont care anymore, the Odac+O2 combo is more than satisfactory as far as im concerned =]

 

i didnt actually try the laptop with the O2, but the hiss was more or less the same on all volumes if i remember correctly... does that make sense?

post #1446 of 3247
Quote:
Originally Posted by mikeaj View Post

 

If I understand you correctly, you have PS3 ---HDMI--->  monitor ---stereo 3.5mm---> O2/ODAC combo to headphones?

 

In general, look for which connections are digital and which are analog.  This means the monitor is responsible for taking the digital audio info and doing the digital-to-analog conversion for sounds coming from the PS3.  It probably has some cheap hardware in there to do that, probably doing a worse job than the PS3 itself would, and worse than the ODAC.  This means you're relying on the monitor for D/A but using the O2 as an amp.  ODAC is bypassed.

 

But I don't think that's likely to "ruin" the sound quality.

Yes, that's the chain that I'm talking about. The main problem of the monitor is that it has a very poor amplifier, that's why I'm using it with the O2, and I know that the monitor DAC is probably poor but I think it's ok for gaming. What I'm asking is if having each of the input connected (but NOT using them at the same time) can generate interferences or any kind of problem while listening music with the PC (I don't think, but you never know).

 

The audio chains are: PC--USB-->ODAC--O2-->HD598 and PS3--HDMI-->Monitor--3.5mm-->O2-->HD598. My question was a little tricky, sorry.


Edited by autior - 5/12/13 at 1:42pm
post #1447 of 3247
Quote:
Originally Posted by adamlr View Post


perhaps it is the source and not the amp, tbh i dont care anymore, the Odac+O2 combo is more than satisfactory as far as im concerned =]

 

i didnt actually try the laptop with the O2, but the hiss was more or less the same on all volumes if i remember correctly... does that make sense?

 

Okay, that's what I expected.  I don't mean to hound a point, but in case anybody was curious, let's say the noise didn't scale at all and you had the source turned down say 25 dB in software compared to max.  Then if you instead use an external amp, you could turn the source to max (25 dB more) and then turn the volume down on the amp to compensate.  If the amp practically doesn't add any more noise of its own, which is what the O2 would do (it has some but very little), then if you're running through the amp, that means you can get 25 dB higher SNR with that setup.

 

 

Quote:

Originally Posted by autior View Post

Yes, that's the chain that I'm talking about. The main problem of the monitor is that it has a very poor amplifier, that's why I'm using it with the O2, and I know that the monitor DAC is probably poor but I think it's ok for gaming. What I'm asking is if having each of the input connected (but NOT using them at the same time) can generate interferences or any kind of problem while listening music with the PC (I don't think, but you never know).

 

The audio chains are: PC--USB-->ODAC--O2-->HD598 and PS3--HDMI-->Monitor--3.5mm-->O2-->HD598. My question was a little tricky, sorry.

 

What I remembered must have been wrong then.  I thought that plugging something into the O2's jack would disconnect the amp from the ODAC.  That's the way I thought it was described on the blog... though really, it depends on how the jack is wired up to the components.  (I think a couple of traces need to be cut on the PCB for that behavior, or... maybe I should just look it up.)  e.g. referenced here:

http://www.jdslabs.com/pdf/Instructions_ODAC_DIY.pdf

 

If both the ODAC and the monitor are hooked up to the O2 simultaneously, that could be a problem, depending on the electronics.  If a device is turned off yet is still physically connected, that can present a weird load to the other device; that's not ideal.  Depends.  If you wanted, you could benchmark the different configurations.  If there's something wrong, it should show up pretty easily (and should be audible, I would think).

 

But if it sounds fine, I wouldn't worry about it.

post #1448 of 3247
Quote:
Originally Posted by autior View Post

Yes, that's the chain that I'm talking about. The main problem of the monitor is that it has a very poor amplifier, that's why I'm using it with the O2, and I know that the monitor DAC is probably poor but I think it's ok for gaming. What I'm asking is if having each of the input connected (but NOT using them at the same time) can generate interferences or any kind of problem while listening music with the PC (I don't think, but you never know).

 

The audio chains are: PC--USB-->ODAC--O2-->HD598 and PS3--HDMI-->Monitor--3.5mm-->O2-->HD598. My question was a little tricky, sorry.

 

Quote:
Originally Posted by mikeaj View Post

 

Okay, that's what I expected.  I don't mean to hound a point, but in case anybody was curious, let's say the noise didn't scale at all and you had the source turned down say 25 dB in software compared to max.  Then if you instead use an external amp, you could turn the source to max (25 dB more) and then turn the volume down on the amp to compensate.  If the amp practically doesn't add any more noise of its own, which is what the O2 would do (it has some but very little), then if you're running through the amp, that means you can get 25 dB higher SNR with that setup.

 

What I remembered must have been wrong then.  I thought that plugging something into the O2's jack would disconnect the amp from the ODAC.  That's the way I thought it was described on the blog... though really, it depends on how the jack is wired up to the components.  (I think a couple of traces need to be cut on the PCB for that behavior, or... maybe I should just look it up.)  e.g. referenced here:

http://www.jdslabs.com/pdf/Instructions_ODAC_DIY.pdf

 

If both the ODAC and the monitor are hooked up to the O2 simultaneously, that could be a problem, depending on the electronics.  If a device is turned off yet is still physically connected, that can present a weird load to the other device; that's not ideal.  Depends.  If you wanted, you could benchmark the different configurations.  If there's something wrong, it should show up pretty easily (and should be audible, I would think).

 

But if it sounds fine, I wouldn't worry about it.

 

My impression was that PC--soundcard-->--3.5mm-->O2-->HD598

Is perfectly fine, basicaly the ODAC would be disabled and the O2 amp active.

 

That is however what I have been told, have not studied any documents regarding the subject.

 

So if wanting to use ODAC then: PC -- USB -- O2 AMP/ODAC -- HD598


Edited by grandpatzer - 5/13/13 at 3:25am
post #1449 of 3247
Quote:
Originally Posted by mikeaj View Post

A lot of times, double amping is really no big deal.  I mean, it's a lot easier for an amp to drive a line input (thousands of ohms impedance, thus low current and so on) than it is for that amp to drive some actual headphones.

 

And DX I think is like D1, which has ~100 ohms output impedance.  It's supposed to be a normal line output that's driven by some high-quality audio op amp that's not particularly some high-current output part.  It's not really much of an amp in the sense that most people are talking about.

This is correct. In some cases, soundcards have 2 'headphone jacks' - the first is a high impedance out (~100 ohms), the other is a dedicated headphone jack (~10 ohms or less).

 

The most current Xonar DX card has 2V out, and dedicated headphone amplification through the front out / Headphone out jack. My guess is that output impedance is probably 10 ohms, given that many good computer cards use TI chips. That is also probably about twice the output voltage typical in a computer. I could not find exact specs online.

 

In either case, the lowest possible distortion is the goal when using a headphone amp as a line out. That said, my line out (100 ohms), and headphone jack sounded exactly the same to me through the O2. If you wanted to, you could use any of the other outputs to listen for an 'audible' difference in outputs. So long as the amplifier is delivering a flat, full-range frequency response, I don't see how 'double amping' can hurt.

post #1450 of 3247
Quote:
Originally Posted by mikeaj View Post

 

Okay, that's what I expected.  I don't mean to hound a point, but in case anybody was curious, let's say the noise didn't scale at all and you had the source turned down say 25 dB in software compared to max.  Then if you instead use an external amp, you could turn the source to max (25 dB more) and then turn the volume down on the amp to compensate.  If the amp practically doesn't add any more noise of its own, which is what the O2 would do (it has some but very little), then if you're running through the amp, that means you can get 25 dB higher SNR with that setup.


hound away =] im sorry but i cant seem to remember where this discussion started... its possible i was mistaken about something, that does tend to happen =\

 

any which way you choose to see it, no noise, is better than some noise. my headphone out on the laptop is very hissy. according to what you wrote i could scale it down using just the O2, but fact of the matter is, using and odac+o2 eliminates the hiss completely, which is important to people like me who listen a relatively low levels, and listen to downtempo\ambient electronica, which has alot of quiet passages.

if your saying that i could have eliminated the noise completely without and external dac (i dont know if 25dB would have done the trick, perhaps they would have) then its already too late - i already got an external dac. i still dont regret it

post #1451 of 3247
Quote:
Originally Posted by adamlr View Post


perhaps it is the source and not the amp, tbh i dont care anymore, the Odac+O2 combo is more than satisfactory as far as im concerned =]

 

i didnt actually try the laptop with the O2, but the hiss was more or less the same on all volumes if i remember correctly... does that make sense?

 

 

Good point. It has not accured to me yet. I'm gonna try:

laptop --> headphone jack ---> O2 --> DT 880 (250 Ohm)

I'll be double-amping, but we shal see.

post #1452 of 3247
Quote:
Originally Posted by mikeaj View Post

What I remembered must have been wrong then.  I thought that plugging something into the O2's jack would disconnect the amp from the ODAC.  That's the way I thought it was described on the blog... though really, it depends on how the jack is wired up to the components.  (I think a couple of traces need to be cut on the PCB for that behavior, or... maybe I should just look it up.)  e.g. referenced here:

http://www.jdslabs.com/pdf/Instructions_ODAC_DIY.pdf

 

If both the ODAC and the monitor are hooked up to the O2 simultaneously, that could be a problem, depending on the electronics.  If a device is turned off yet is still physically connected, that can present a weird load to the other device; that's not ideal.  Depends.  If you wanted, you could benchmark the different configurations.  If there's something wrong, it should show up pretty easily (and should be audible, I would think).

 

But if it sounds fine, I wouldn't worry about it.

I'll do some tests then, thanks for the answers.

post #1453 of 3247

Has anyone tried to build an ODAC+O2 combo that can run off of a battery?

 

I know someone mentioned it here, oh tens and tens of pages ago, that they managed to it by flipping the PCB upside down.

 

If it can do that with a rechargable battery, and be able to play and charge at the same time, I would be SOOOOO happy.
 

post #1454 of 3247
Quote:
Originally Posted by Bojamijams View Post

Has anyone tried to build an ODAC+O2 combo that can run off of a battery?

 

I know someone mentioned it here, oh tens and tens of pages ago, that they managed to it by flipping the PCB upside down.

 

If it can do that with a rechargable battery, and be able to play and charge at the same time, I would be SOOOOO happy.
 

 

I have built several for friends/family, but used larger cases (such as Box Enclosure B3 / B4, a Hammond, and a Context Eng). I figured that in 99% of scenarios where a device needs a USB DAC, said device would be a computer, not a smartphone, so the amp just had to be transportable, not pocket portable. The DAC is bus powered so it doesnt have anything to do with the batteries, except take up too much space in the B2 case. In theory, it could be done with a smaller case but you'd have to (1) cover the ODAC in electrical tape to prevent shorts and (2) solder your battery terminals straight and very low. With the batteries touching the O2 board, you *might* have just barely enough clearance to fit the ODAC board, but again, it'd be touching the top case so you'd have to cover it thoroughly. I honestly wouldn't recommend this as the tight fit could damage that board. The batteries just take up too much space in a B2. In most cases, your terminals won't be soldered that neatly; in my current O2 that I built, the batteries themselves touch the top case and were a tight fit to slide the O2 board in, that's how tight the clearances are.

 

My recommendation? Get a B3-080 case. It's only a dollar or so more expensive from Allied Elec.


Edited by tintin220 - 5/14/13 at 7:57am
post #1455 of 3247
Quote:
Originally Posted by Bojamijams View Post

Has anyone tried to build an ODAC+O2 combo that can run off of a battery?

 

I know someone mentioned it here, oh tens and tens of pages ago, that they managed to it by flipping the PCB upside down.

 

If it can do that with a rechargable battery, and be able to play and charge at the same time, I would be SOOOOO happy.

 

 

You don't mean where the O2 is also powered off of USB, right?  

 

As mentioned above, just fitting the ODAC in is a matter of space.  No reason you can't have both the 9V batteries and the ODAC in the same enclosure, especially if the enclosure is larger than the default one.  It's just that most builders just usually put the ODAC in the space where the batteries would have been, out of convenience, when putting both ODAC and O2 in the same case.


Edited by mikeaj - 5/14/13 at 10:09am
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